PS:
> if you want to 
> optimize then choose a central, high-level, intent revealing 
> place (such as, in fact, SortedCollection>>addAll:) and don't 
> ever have the client second-guessing the structure and 
> behavior of the object in question.

A good example of what I mean can be found if you browse the
implementors of #atAllPut: - it contains specific optimizations for
polymorphic receivers and you simply can not get any faster by "client
side optimizations" (e.g., writing out the loop or similar). But such a
critical place has to be identified first and if everyone is
"optimizing" the code locally you will never find the bottleneck to
begin with.

Cheers,
  - Andreas